Aza trinuclear cyanine dyes



Patented Dec. 26, 1950 UNITED :S TATES PAT E N T O FFI C E AzA'rRINUcLEAR CYANINE DYES Henry '=l)erbysliire, Johnson City, N. Y., as-

signor to General Aniline & Film Corporation,

New York, N. Y., a corporation of Delaware No Drawing. Application December 16, 1949, Serial No. 133,474

4 Claims. (Cl. 260-2401) 1 2 This invention relates to trinuclear cyanine quaternary salt, containing .a particular reactive dyes of the rhodacarbocyanine type containing group, of the type commonly-employed -in cyanine an aza(=N) group in the chromophoric chain, dye syntheses with an azathiazolone cyanine dye and particularly to an improved method of prein a suitable solvent, such as an aliphatic alcohol, paring the same. 5 e. g., methyl, ethyl, n-propyl, isopropyl,:-and the f l rinuclearcyanine dyes of the rhodac'arbocym like, in the presence of a basic condensing agent, nine type containing an-a'za group in the chromosuch as sodium methylate, trimethylamine, triphoric =chain have been prepared by the method ethylamine, pyridine, methylpyridine, ethylpyridescribed in United StatesT-Patent2388g963. 'Whe dine, quinoline, potassium carbonate, and the method consists of first quaternizing a -cyc lamlike. at room temperature forahout -1 houror-by monium base, containing a reactive thiol group, simply heating the reaction mixture :for a matter and condensing "it with an N-ethylrhodanic acid of minutes, either by boiling or at reflux. to obtain the meroc-yanine intermediate. This The dyes obtained by the aforegoing procedure procedure involves two steps and requires about are characterized by the following general for- 4 hours time. The merocyanine intermediate mula:

tuted cyclammonium base and a quaternizing tive integer of from 1 to 3, R andRz are the same agent, such as methyl .p-toluenesulfonate for 2 or different and represent alkyl, aryl, or aralkyl to 3% hours. After cooling the melt, .pyridineis or substituted groups of this type, e. g, methyl, added and the mixture reheated, under reflux, for ethyl, propyl, isopropyl, n-butyl, fisobutyl, n-amyl, 20 to minutes. The reactive mixture is iithen isoamyl, hydroxyethyl, y-hydroxlpropyil, .p-me'thpoured into an aqueous solution of potassium oxyethyl, B-ethoxyethyl, allyl, phenyl, p-tolyl, bromide and the final dye obtained byzrecrystalli- 30 o-tohd, u-naphthyl, p-inapiithyl benzyl, "mena'phzation from alcohol. The minimum time rethyl, p-phenylethy=L qi-carboxyet'hyl, carbonyquired for the latter two steps is approximately methyl, a-carboxyethyl, y-carboxypropy l, pacefrom 3 to 4 hours, exclusive of the time required tox-yethyl, iy-acetopropyl, cambomethoxymethyl, to cool the reaction mixture. The process steps 18 carbomethoxymethyl, 8 carboethoxymethyl, involved in this preparation are not only tedious, naphthylmethyl, and the like, R1 represents an but time consuming. allyl or analkyLaryl oraralkyl group of the same It is an object of the present invention to provalue as R, R represents either hydrogen er a vide an improved and simplified method for the lower alkyl group, e.g., methyl,'ethyl,propyl, etc., preparation of trinuclear cyanine dyes contain- 40 and lower :alkyl only when m. 'is 2,.Xrepresents'an ing an aza group in the chromophoric chain. acid radical, :e. :g., chloride, bromide, iodide, 13er- A further object of the present invention is to chlorate, and the like, Z and .Z' are the same or provide a method of producing rhodacarbocyadifferent and represent the residues of heteronine dyes, containing an 9,221. group in the chrocyclic nitrogenous nuclei of the type common in mophoric chain, without afirst forming the usual cyaninedyes e. g oxazoles, thiazoles,-selenazoles, merocyanine dye intermediates. and their polycyolic hiomologu'es, such as those A still further object is to provide a simple or the benzene, naphthalene, .acenaphthene and method of obtaining,inexcellentyield, trinuclear anthracene series, pyridine, and fits polycyclic cyanine dyes containing an aza group in the homologues, such as quino'line and aand e chromophoric chain. naphtha'quinolines, indolenines, :benzimidazoles, Other objects and "advantages will :become :ap d-ia'zines, :such as pyrimidines and quinazolines, parent from the following description. thiazolines :and .selenazoiines. .The polycyclic I have found that trinuclear cyanine dyes, concompounds of this series mayalso "be substituted taining an aza group in the chromophoric chain, in the carbooylic rings with one or more groups,

are prepared in excellent yield and in readily such asalkyl,itre niethyl, ethylg'eta, aryl, i. e., purifiable form by treating a .lcyclammonium phenyl oramino, hydroxy,alkoxy,i.e., methoxy,

ethoxy, etc., and methylene-dioxy groups, or by halogen, i. e., chlorine, bromine or iodine atoms.

As illustrative examples of nitrogenous heterocyclic nuclei of the class common in cyanine dyes, the following may be mentioned:

Thiazoles, e. g., 4-methylthiazole l-phenylthiazole 4,5-dimethylthiazole 4,5-diphenylthiazole 5-methylthiazole 5-phenylthiazole 4-(2-thienyl)thiazole, and the like, Benzthiazole, e. g., benzothiazole -chlorobenzothiazole S-chlorobenzothiazole fi-chlorobenzothiazole 7-ch1orobenzothiazole -methylbenzothiazole 5-methylbenzothiazole G-methylbenzothiazole 4-methoxybenzothiazole 5 methoxybenzothiazo1e G-methoxybenzothiazole S-bromothiazole B-bromothiazole 5-iodobenzothiazole 6-iodobenzothiazole -phenylbenzothiazole fi-phenylbenzothiazole 4-ethoxybenzothiazo1e 5-ethoxybenzothiazole Tetrahydrobenzothiazole 5,6methoxybenzothiazole a-Naphthiazoles ,B-Naphthiazoles Benzoselenazoles, e. g., benzoselenazole 5-methoxybenzoselenazole 5-chlorobenzoselenazole 5-methylbenzoselenazole Tetrahydrobenzoselenazole, Thiazolines, e. g., 3,3-dimethylthiazoline Quinoline, e. g., quinoline, G-methylquinoline '7-methylquinoline 8-methylquinoline fi-chloroquinoline 8-chloroquinoline 5,6-benzoquinoline, and the like.

The dyes are obtained by heating an azathiae zolone cyanine dye with any cyclammonium quaternary salt of the type commonly employed in cyanine dye synthesis containing from 5 to 6 atoms in the heterocyclic ring and containing a reactive group in either alpha-, beta-, or deltaposition of the side chain in 2-position of the nitrogen atom thereof, at room temperature for about an hour, or by heating the reaction mixture for a matter of minutes in the presence of a basic condensing agent, such as sodium methylate, trimethylamine, triethylamine, pyridine, methylpyridine, ethylpyridine, quinoline, and the like.

The azathiazolone cyanine dyes, utilized as ooreactants with the foregoing cyclammonium quaternary salts are prepared according to the method described in my application Serial No. 133,473, filed on even date. In general, the method involves condensing an appropriately substituted heterocyclic thiourea with an a-halogen acetic acid. The condensation reaction between the substituted thiourea and a-halogen acetic acid is carried out, as pointed out above, by simply heating the coreactants at a temperature ranging from 100-l50 C. for 3 to 6 hours.

The reaction can also be effected by heating the coreactants in the presence of an alcohol or glacial acetic acid for a few minutes at reflux or on a steam bath. I prefer for the sake of expediency to operate by heating the coreactants in the presence of butyl, amyl, or isobutyl alcohol and the like or in the presence of glacial acetic acid at a temperature ranging from 75-150" C. for a period of time ranging from 5 minutes to 1 hour.

The reaction involved in this case by utilizing, for example, chloracetic acid is believed to take place as follows:

i It:

ill

wherein m, R, R1, X and Z have the same values as above, and R3 represents an alkyl, allyl, aryl, or aralkyl group of the same value as in R1.

The cyclammonium quaternary salts of the type commonly employed in cyanine dye synthesis containing a reactive group referred to above and heated with the azathiazolone cyanine dye are characterized by the following general formula:

wherein m, R2, X and Z have the same values as above, and Y represents a reactive group in a reactive position, i. e., from alphato delta-position of the side chain in 2-position of the nitrogen atom of said cyclammonium quaternary salt, such as, for example:

Alkylmercapto, e. g., methylmercapto Ethylmercapto Propylmercapto Butylmercapto Arylmercapto, e. g., phenylmercapto Tolylmercapto Naphthylmercapto, etc.

,B-Alkylmercaptovinyl, e. g., p-methylmercaptovinyl fl-Ethylmercaptovinyl e-Propylmercaptovinyl p-Butylmercaptovinyl ,e-Arylmercaptovinyl, e. g., s-phenylmercaptovinyl fi-Tolylmercaptovinyl e-Naphthylmercaptovinyl p-Alkylmercapto-B-alkylvinyl, or

fl-Alkylmercapto-13-arylvinyl, e. g., p-methylmercapto-e-methylvinyl e-Methylmercapto-p-ethylvinyl B-Methylmercapto-fl-propylvinyl ,s-Methylmercapto-fi-butylvinyl 5-Ethylmercapto-,8methylvinyl e-Ethylmercapto-p-ethylvinyl p-Ethylmercapto-,8-buty1vinyl e-Butylmercapto-{3-ethylvinyl ,B-Butylmercapto-p-propylvinyl [3-Butylmercapto-B-butylvinyl [3Ethyl1nercapto-fl-phenylvinyl, and the like,

p-Aminovinyl and polyvinyl compounds, e. g.,

,B-anilinovinyl apaaess B-Acetanilidovinyl p-Piperidinovinyl p-Morpholinovinyl 4-acctanilido-1,3-butadienyl 4-anilino-L3-butadienyl i-piperidine-1,3-butadienyl 4-morpho1ine-l ,S-butadienyI G-acetanilido-1,3,5-hexatrienyl 6-anilino-1,3,5-hexatrienyl 6-piperidino-1,3 -hexatrieny1 6-morpholino-1,3,5-hexatrienyl These ,p-arylaminovinyl compounds are known for the most part and can the prepared by .fusing a ldiarylformamidine with a .cyclammonium quaternary salt containing a reactive methyl group. The acylarylaminovinyl compounds are formed by heating the diarylformamidine with the cyclammonium quaternary salt in .a carboxylic anhydride, e. g., acetic,v propiom'c, .or butyric anhydride.

As typical examples *of cyclammonium quaternary salts useful in the condensation of the azathiazolone cyan'ine dye, the :followi-ngmay be mentioned:

2-methyl-mercaptobenzothiazole ethiodide 2-phenylmercaptobenzothiazole ethiodide 2- (B-acetanilidovinyl) benzoxazole ethiodide 2- (fi-acetanilidovinyl) benzothiazole 2- (fl-acetanilidovinyl) quinoline ethiodide 4:- fi acetanilidovinyD'qui-noline n-butiodide Z-Qe-acetanilidovinyl B naphthothiazole ethiodide Z-anilinoyiny-lthiazoline methio'dide 2- (,8acetanilidovinyl) benzothiazole pheniodi'de 2- (e-acetanilidovinyl) benzoselenazole ethiodide 2-(p-acetanilidovinyl) 4 phenylthiazole ethiodide 2-(fi-acetanilidovinyl) -3,3 dimethylindolenine methiodide 2- (,6- [N-methylanilino]vinyl-henzothiazole ethiodide Z-(fl-acetanilido) -3,4 trimethylenebenzothiazolium iodide 2-(5-anilinovinyl) 3 phenylthiazolinium perchlorate 2-(13-anili-novinyl) -3 (wnaphthy-Dthiazofinium perchlorate, etc

2- a-ethyl-p-methylmercaiptovinyli'benzothiazole ethiodide 2-(p-acetani1idovinyl) benzoxazole meth-iodide 2- (4;-acetanilide- 1,3 butadi'enyl) benzothiazole ethiodide 2-(6-anilino 1,3,5 hexatrienyl)ibenzothiazole ethiodide,

and the like.

The following examples are illustrative of the method used in preparing the azathiazolone cyam'ne dyes.

Example I N- (3-ethyl 2-benzothiazolylidene) -N -pheny1thiourea 5.5 grams of Z-aminobenzothiazole ethiodide and 5 grams of phenyl isothiocyanate were dissolved in mls. of hot pyridine. The solution was heated slowly until its temperaturereached 8 :C. Upon-c'ooling to 259 8., a yellow solid crystalized which was filtered off, washed 1 with water, dried, and purified by recrystallization from methanol. Theproduct was, dried at 85 C. The yield was 5.4 grams melting at 158 C.

Example II .N-fwe th yllalisethoxywbenzotliiazolyliiiene) N rphenylthiourea 8 grams of 2-amino-6 ethoxybenzothia"zole ethiodide and 5 grams of :phenyl isothiocyanate were dissolved in 10 mls. of boiling pyridine. The resulting solution was stirred and slowly heated to 150 C. while'permit'ting the pyridine to distill off at this point. Heating was discontinued, but stirring was kept up until the reaction mass cooled to 25 0. A yellowish solid separated which was washed with two 25 ml. portions of water, then triturated with 20 mls. of methanol and filtered. After consecutive washings with water and methanol, the .solid was dried overnight at 80 C. 6 grams of a purified product were obtained which melted at 177 -1580 0..

Example III '7 grams of 2-'a'mino='6*ethoxybenzothiazole ethiodide and 5 grams of allyl isothiocyanate were heated together in 5 mlsaof boiling pyridine. Heating was continued until the internal temperature reached 150 C. The reaction mixture was cooled to room temperature and poured into 10 mls. of water. The yellow solid which separated was triturated with three fresh 10 ml. portions of methanol, filtered, washed alternately with water and methanol, and dried. Th'eprod-uct melted at 119422 C,

Example IV N- (3 ethyl-5-methyl-Qphenyl-Z thiazolylidene) -N-- phenylthiourea 6 grams, of 2-amino-5-methyl-4-phenyl-2- thiazole ethiodide and 4 grams of phenyl isot hiocyanate were dissolved in 10 mls. of hot pyridine. The resulting solution was heated until its internal temperature reached C. The mixture was stirred slowly until cooled to 25 C. A solid separated which was -.diluted with 10 mls. of isopropyl alcohol, filtered, repeatedly washed 7 with isopropyl alcohol and dried. 4.7 grams of a lemon-white solid was obtained which melted at 183-185 C.

Example V (fur N- (3-methyl-2-benzotl1iazolylldene) -N-phenylthiourea This product was prepared from 5 grams of 2- amino-benzothiazole methiodide and 5 grams of phenylisothiocyanate by following the general procedure of Example I.

Example VI S o fi OER-( J C: I

N (3,4-dimethyl-2thiazolylidene N-phenylthiourea 100 grams of Z-amino--methylthiazole dimethylsulfate and 5.7 grams of phenyl isothiocyanate were heated slowly together until the temperature of the reaction mixture reached 140 C. At this point, heating was discontinued and the mass was stirred constantly until it had reached room temperature. Crystals separated when the mass was diluted with a mixture of 200 mls. of equal parts of water and isopropanol. The crystals were filtered oil, washed in isopropyl alcohol, and dried.

Example VII s S-OH2 C N=l N/ One gram of the product of Example V and 1 gram of bromoacetic acid were dissolved in 5 mls. of glacial acetic acid and heated for 5 minutes. The solution was cooled to room temperature, diluted with mls. of ether, and stirred vigorously until a, yellow fiufiy solid separated. The crystals were filtered oil, and repeatedly washed with ether.

Example VIII MJ EZL 5.4 grams of the compound of Example I and 5 grams of bromoacetic acid were boiled together in mls. of glacial acetic acid for 5 minutes. The cooled solution was poured into 40 mls. of ether.

A yellow crystalline solid precipitated which was washed with ether.

5 grams of the product of Example IV and 3 grams of bromoacetio acid were heated together for 30 minutes in boiling n-butanol. The mixture was cooled in ice and stirred until muddyyellow crystals separated. After 10 mls. of isopropanol had been added, the crystals were filtered off, and washed with ether.

This product was obtained in the form of a fine yellow solid prepared from 2 grams of the compound of Example III and 2.2 grams of bromoacetic acid by following the procedure of Example VI.

Example XI This product was obtained by a process analogous to the one described in Example VII but using 3.8 grams of the compound of Example II and 4 grams of bromoacetic acid as starting materials.

Example XII Example VIII was repeated with the exception that 3.4 grams of chloroacetic acid were used in place of 5 grams of bromoacetic'acid.

Example XIII 9 10 One gram of. the compound: of. Example VI which was filtered-and washed with isopropanol. and- 1 gram of bromoacetic acid were heated to,- The dye was purified bycrystallization from 25 getherfor 2. minutesin the presence of 10 mls. mls. of methanol. Itmelted with decomposition ofglacial acetic acid. Thepale yellow solution at 263 C.

.was cooled to roomtemperature, diluted with30 5 The methanol solution of the dye showed an mls. of ether, decanted and ,triturated. with an obsorption maximum at 461 m and sensitized a additional 30 mls. of anhydrousether; A gummy silver chlorobromide emulsion to 540 m with a solid was obtained which. was used directly in maximum at 480 m dye synthesis.

The foregoing thiazolonecyanine dye salts may a Example XVI be converted to salts other than halogen by treating an alcohol solution of the halogen salt with an aqueous or aqueous-alcohol solution containing a sodium or potassium salt of perchlorio, hydroiodic, or thiocyanic acid;

The following examples describe in detail the method of preparing the trinuclear dyes of the present invention, but it is to be understood that they are given merely for the purpose of illustration and are not to be construed as limitative. 2- grams of Z-(fi-acetanilidovinyl)benzoxazole Example XIV ethiodide and 0.8 gram of the compound of Example IX were heated together in 50 mls., of methanol containing 25 drops of triethylamine. 2 5 The crystals, which separated upon cooling and stirring, were filtered ofi, washed with methanol N and dry ether, and recrystallized from methanol. an, The purified product has a melting point of l 192-194" C. A methanol solution showed an 30 absorption maximum at 521 m and extended the range of sensitization ofa silver bromoiodide 1 emulsion to 605 m Two. grams of 2. 6.6-acetan lidovinynbenzoxa- Example XVII x A o O 11 q=oc oH=o. \z #0021! V ,i \N/ 0=1 =N-C (E N t H: (lJ .N

- Ha I (I) 02H: 11 OH: 0104 zole ethiodide and 0.75 gram of the product of 1.4 grams of theproduct of Example X and 1 Example VIII were dissolved in 50 mls. of methgram of 2 (B acetanilidovinyl) -5-methyl-4- anol. After the addition of drops of triethylphenyloxazole methiodide were dissolved in 20 amine, the solution was heated and kept refluxmls. of boiling methanol. drops. of triethyling for 15 minutes. When the solution-was cooled amine were added and boiling continued for 1 to room temperature, purple crystals separated minute. After cooling; l0 mls. of an aqueous which were washed with ethanol and ether and b9 by Weight solution of sodium perchlorate recrystallized from mls. of methanol. Blue were added. The precipitate obtained was puricrystals melting above 250 C'. were obtained. A fled by crystallization from methanol and has solution in ethanol showed a blue appearance a melting point of 184 C. A methanol solution with an absorption maximum at 534 m A Ldye showed an absorption maximumat 535 m and sensitized photographic chlorobromide emulsion extended the sensitization range of a silver to 620 m with a sensitization maximum at chlorobromide emulsion to 650 m I 1.5 grams of Z-methylmercaptobenzoselen- 0.7 gram of the compound of Example VH1 79 azole methiodide and 0.75 gram of the compound and 0.8' gram of 2-ethylmercaptobenzothiazole of Example XE were dissolved in 10 mls. of

ethyl p -toluenesulfonate were dissolved in 10 mls. methanol and heated to boiling. An orangeof warm methanol. 25 drops of triethylamine red solid began to form immediately when 15 were added and the mixture brought to boiling. drops of triethylamine were added to the solu- Upon cooling an orange-yellow" solid separated, tion. After" cooling and filtering, the solid was 11 washed with water and recrystallized from methanol. It melted at 195 C. A solution in methanol showed an absorption maximum at 469 mm and extended the sensitization range of a silver chlorobromide emulsion to 560 m One gram of 2-ethylmercaptobenzothiazole ethyl p-toluenesulfonate and 1.5 grams of the compound of Example XI were dissolved in 10 mls. of boiling methanol. Twenty mls. of triethylamine were added and the precipitated mass agitated until cooled to room temperature. The yellow solid was filtered ofi, washed several times with water, and twice recrystallized from methanol. The crystals obtained melted at 330-335 C. A methanol solution showed an absorption maximum at 467 m and extended the sensitization range of a silver chlorobromide emulsion to 550 mu.

Ewample XX $11 HIE:

0.5 gram of the product of Example X and 1 gram of 2-ethylmercaptobenzothiazole ethyl ptoluenesulfonate were dissolved in 30 mls. of methanol. A precipitate began to form when 30 drops of triethylamine were added to the solu tion, and the mixture soon became a thick paste. The suspension was diluted with 20 mls. of methanol and filtered. The crystals were washed with a 1: 1 mixture by volume of methanol and water, and twice recrystallized from methanol. The crystals obtained melted at 234-235 C. A methanol solution showed an absorption maximum at 460 m and extended the sensitization range of a silver chlorobromide emulsion to 540 m 1.5 grams of the product of Example VIII and 1.5 grams of 2-(B-acetanilidovinyl) -5,6-dimethylbenzoxazole ethiodide were dissolved in 20 mls. of methanol by gentle boiling. One ml. of triethylamine was added and the mixture stirred for 5 minutes. A dye separated which was filtered off, washed with water and after drying, twice recrystallized from methanol. The purified product melted at 238-240 C. Its methanol solution showed an absorption maximum at 543 ma and extended the sensitization range of a silver chlorobromide emulsion to 630 ma.

Example XXII CHlO Example XXIII This product was prepared from 0.5 gram of the solid of Example XIII and 1.5 grams of 2- (B acetanilidovinyl) 5,6 dimethylbenzoxazole ethiodide following the procedure of Example XIV. The product obtained melted at 260-26'7 C. with decomposition. A methanol solution showed an absorption maximum at 524 m and extended the sensitization range of a silver chlorobromide emulsion to 630 ml.

Example XXIV OH: I (32H! 0.5 gram of the intermediate of Example IV and 1 gram of bromacetic acid were boiled for two minutes in 5 mls. of glacial acetic acid. After cooling to 30 C., 8 volumes of ethyl ether were added and the azathiazolone cyanine, which precipitated, filtered off, washed with ether, and

immediately dissolved in mls. of isopropanol. One gram of 2(,3-ethyl-g-methylmercaptovinyl) benzothiazole ethiodide was added and the solution brought to boiling. To the hot solution, 2 mls. of triethylamine were added and heating continued for 5 minutes. The mixture was allowed to cool; the dye crystals which formed were removed by filtration and purified by crystallization from 25 mls. of methanol. The green dye crystals melted at 261-263 0., and their solution in methanol showed an absorption maximum at 559 me.

While I have disclosed the preferred embodiments of my invention and the preferred modes of carrying the same into effect, it will be readily apparent to those skilled in the art that many variations may be made therein, without departing from the spirit thereof. Accordingly, the scope of my invention is to be limited solely by the appended claims.

I claim:

1. A process for the production of trinuclear cyanine dyestuffs comprising treatin an azathiazolone of the general formula:

with a cyclammonium quarternary salt of the general formula:

wherein Z and Z are selected from the group consisting of residues of heterocyclic nitrogenous compounds of the type usual in the preparation of cyanine dyes, m represents an integer of from 1 to 2, R and R2 are each selected from the group consisting of alkyl, hydroxyalkyl, alkoxyalkyl, aryl and aralkyl groups, R1 is selected from the group consisting of alkyl, allyl, aryl and aralkyl groups, X represents an acid radical and Y represents an active group selected from the class consisting of alkylmercapto, arylmercapto, fl-alkylmercapto, fi-arylmercaptovinyl, p-alkylmercapto-[i-alkylvinyl, [i-alkylmeroapto-e-arylvinyl, fl-anilinovinyl, fi-acetanilidovinyl, fi-piperidinovinyl, fi-morpholinovinyl, 4-acetani1ido-L3-butadienyl, -anilino-1,3-butadienyl, 4-piperidine-1,- 3-butadienyl, -morpholine-LB-butadienyl, 6- acetanilido-l,3,5-hexatrieny1, 6anilino-l,3,5-hexatrienyl, S-piperidine-1,3,5-hexatrienyl, and 6- morpholino-l,3,5-hexatrienyl.

2. A process for the production of a trinuclear dyestufi characterized by the following formula:

which comprises treating a thiazolone of the following formula:

with 2-(fi-acetanilidovinyl)benzoxazole ethiodide in the presence of an aliphatic alcohol and a basic condensing agent.

3. A process for the production of a trinuclear dyestuif characterized by the following formula:

CzHs

which comprises treating a thiazolone of the following formula:

with Z-methylmercapto-5-methoxybenzoselena zole methosulfate in the presence of an aliphatic alcohol and a basic condensing agent.

4. A process for the production of a trinuclear dyestuff characterized by the following formula:

Er with 2- 3-ethyl- 8-methylmer captovinyl) benzothiazole ethiodide in the presence of an aliphatic alcohol and a basic condensing agent.

HENRY G. DERBYSHIRE. No references cited. 

1. A PROCESS FOR THE PRODUCTION OF TRINUCLEAR CYANINE DYESTUFFS COMPRISING TREATING AN AZATHIAZOLONE OF THE GENERAL FORMULA: 